This type of clip comprises two parts of a grommet and a pin. The grommet has a flange and leg pieces. The leg pieces is pushed into a fixing hole of an object to be fixed. When the pin is pushed into the center axial portion of the grommet, the pushing pressure of the pin acts on the leg portions, so that the leg pieces expand outwards. The grommet is fixed to the fixing hole of the object to be fixed as described above.
A clip in which a grommet and a pin are integrated with each other by partially joining them is known as one of this type of clips.
For example, Such a type of clips that parts other than the flange of the grommet are joined to the pin are disclosed in U.S. Pat. Nos. 4,312,614, 5,028,187, 5,689,863, 6,511,273, 7,018,152, US2004-0181917A1, etc.
With respect to the clips disclosed in these patent documents, a mold is opened and closed in the lateral direction to demold a grommet and a pin integrally. Accordingly, in order to demold the pin disposed at the center axial portion of the grommet, it is necessary to bisect the flange of the grommet and demold the pin from the interval between the respective bisected flanges.
Therefore, the flange of the grommet has a bisection structure, and thus there is a disadvantage that when the leg pieces of the grommet are pushed into the fixing hole of the object to be fixed, it is difficult to apply uniform pressure to the grommet and thus it is hard to handle the grommet.
On the other hand, there is known a clip in which the flange of the grommet is not bisected and the grommet is joined to the pin by the flange. This type of clips are disclosed in U.S. Pat. Nos. 4,276,806, 4,405,272, 4,856,950, US2005-0220561A1, etc.
With respect to the clips disclosed in these patent documents, a mold is inserted in the center axial direction of the grommet to demold the pin. Therefore, plural leg portions extending from the flange of the grommet are respectively separated from one another, and the leg portions are independent of one another.
The fixing hole of the object to be fixed may be located at a deep place, a step portion or the like, or it may be located at the back side of an interior or exterior part when viewed from a worker, so that the worker hardly visually recognize the fixing hole directly. In this case, the position of the fixing hole is groped or estimated on the basis of the relative positional relationship with other parts surrounding the fixing hole, the tips of the leg portions of the grommet are inserted into the fixing hole, and then the leg portions of the grommet are pushed in. A remarkable skill is required to push the independent plural leg portions into the fixing hole in a short time with no trouble by such a groping work.
Furthermore, U.S. Pat. Nos. 4,571,134 and 5,704,746 disclose clips having the structure that the flange is not segmented, plural leg pieces are joined to one another at the tips thereof, and the pin is joined to the flange of the grommet. The clips disclosed in these patent documents are constructed so that the lower end of the pin is joined to the flange. That is, the pin extends to the surface side of the flange and it is pushed to smash through the flange and intrude into the back surface of the flange. The clips discloses in the U.S. Pat. Nos. 4,276,806 and 4,856,950 have the same construction.
In the constructions as described above, it is necessary to accurately apply pressure to the pin in the axial direction, and when a bending moment acts on the pin, the pin turns over and thus it cannot be pushed into the back surface side of the flange.